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Published on: April 25, 2025
The effect of manuka honey on the structure of Pseudomonas aeruginosa
A F Henriques1, R E Jenkins, N F Burton
1Centre for Biomedical Sciences, Cardiff School of Health Sciences, University of Wales Institute Cardiff, Western Avenue, Cardiff, CF5 2YB, UK.
Abstract:
The purpose of this study was to investigate the effects of manuka honey on the structural integrity of Pseudomonas aeruginosa ATCC 27853. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of manuka honey for P. aeruginosa were determined by a microtitre plate method, and the survival of bacteria exposed to a bactericidal concentration of manuka honey was monitored. The effect of manuka honey on the structure of the bacteria was investigated using scanning and transmission electron microscopy (SEM and TEM, respectively). The MIC and MBC values of manuka honey against P. aeruginosa were 9.5% (w/v) and 12% (w/v) respectively; a time-kill curve demonstrated a bactericidal rather than a bacteriostatic effect, with a 5 log reduction estimated within 257 min. Using SEM, loss of structural integrity and marked changes in cell shape and surface were observed in honey-treated cultures. With TEM, these changes were confirmed, and evidence of extensive cell disruption and lysis was found. Manuka honey does not induce the same structural changes in P. aeruginosa as those observed in staphylococci. Our results indicate that manuka honey has the potential to be an effective inhibitor of P. aeruginosa.
Insights
Manuka honey damages Pseudomonas aeruginosa by disrupting its cell structure, showing potential as an effective antibacterial agent. This study determined its minimum inhibitory and bactericidal concentrations and observed significant structural damage via electron microscopy.
Area of Science:
- Microbiology
- Biochemistry
- Materials Science
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen.
- Manuka honey possesses antimicrobial properties.
- Understanding honey's effect on bacterial structure is crucial.
Purpose of the Study:
- To investigate manuka honey's impact on Pseudomonas aeruginosa structural integrity.
- To determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of manuka honey.
- To elucidate the mechanism of action using electron microscopy.
Main Methods:
- Microtitre plate method for MIC and MBC determination.
- Time-kill curve analysis for bacterial survival.
- Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for structural analysis.
Main Results:
- MIC and MBC values were 9.5% (w/v) and 12% (w/v), respectively.
- Manuka honey exhibited a bactericidal effect, achieving a 5 log reduction in 257 minutes.
- SEM and TEM revealed loss of structural integrity, cell shape changes, surface alterations, disruption, and lysis.
Conclusions:
- Manuka honey effectively inhibits Pseudomonas aeruginosa growth and causes significant structural damage.
- The mechanism involves cell disruption and lysis, distinct from effects on staphylococci.
- Manuka honey shows promise as a therapeutic agent against Pseudomonas aeruginosa infections.
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